Updated Test sample

Author: SubhikshaSf4851

src/Controls/src/Core/Handlers/Shell/ShellHandler.Windows.cs

@@ -129,6 +129,7 @@ public static void MapFlyoutBackground(ShellHandler handler, Shell view)
 					view.FlyoutBackgroundColor?.AsPaint());
 		}
 
+		//TODO: Make it public in .NET 10.
 		internal static void MapFlyoutBackgroundImage(ShellHandler handler, Shell view)
 		{
 			var provider = handler.GetRequiredService<IImageSourceServiceProvider>();

src/Controls/tests/TestCases.HostApp/Issues/Issue21472.cs

@@ -6,7 +6,7 @@ public class Issue21472 : Shell
 	public Issue21472()
 	{
 		FlyoutBackgroundImage = "dotnet_bot.png";
-		FlyoutBehavior = FlyoutBehavior.Locked;
+		FlyoutBehavior = FlyoutBehavior.Flyout;
 		FlyoutBackgroundImageAspect = Aspect.AspectFill;
 		var flyoutItem1 = new FlyoutItem { Title = "Item1" };
 		var tab1 = new Tab();
@@ -20,12 +20,19 @@ public class Issue21472ContentPage : ContentPage
 {
 	public Issue21472ContentPage()
 	{
-		Content = new Label
+		var button = new Button
 		{
-			Text = "Flyout Should Contain backgroundImage",
+			Text = "RemoveFlyoutBackground",
 			HorizontalOptions = LayoutOptions.Center,
 			VerticalOptions = LayoutOptions.Center,
-			AutomationId = "label"
+			AutomationId = "button"
 		};
+
+		button.Clicked += (sender, e) =>
+		{
+			Shell.Current.FlyoutBackgroundImage = null;
+		};
+
+		Content = button;
 	}
 }

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue21472.cs

@@ -10,11 +10,22 @@ public Issue21472(TestDevice testDevice) : base(testDevice)
 	}
 	public override string Issue => "Shell FlyoutBackgroundImage doesn't shown";
 
-	[Test]
+	[Test, Order(1)]
 	[Category(UITestCategories.Shell)]
-	public void ShellFlyoutBackgroundImageVerify()
+	public void VerifyShellFlyoutBackgroundImage()
 	{
-		App.WaitForElement("label");
+		App.WaitForElement("button");
+		App.ShowFlyout();	
+		VerifyScreenshot();
+	}
+
+	[Test, Order(2)]
+	[Category(UITestCategories.Shell)]
+	public void VerifyShellFlyoutBackgroundImageSetNull()
+	{
+		App.WaitForElement("button");
+		App.Tap("button");
+		App.ShowFlyout();
 		VerifyScreenshot();
 	}
 }

src/Core/src/Platform/Windows/NavigationViewExtensions.cs

@@ -270,6 +270,12 @@ internal static async Task UpdateBackgroundImageSourceAsync(this MauiNavigationV
 
 			var service = provider.GetRequiredImageSourceService(imageSource);
 			var nativeImageSource = await service.GetImageSourceAsync(imageSource);
+			
+			if (nativeImageSource is null)
+			{
+				paneContentGrid.Background = null;
+				return;
+			}
 
 			var BackgroundImage = new ImageBrush
 			{